//public IEnumerable<TIfcType> OfType<TIfcType>() where TIfcType : IPersistIfcEntity
//{
// return cache.OfType<TIfcType>(false);
//}
/// <summary>
/// Filters the Ifc Instances based on their Type and the predicate
/// </summary>
/// <typeparam name = "TIfcType">Ifc Type to filter</typeparam>
/// <param name = "expression">function to execute</param>
/// <returns></returns>
public IEnumerable <TIfcType> Where <TIfcType>(Expression <Func <TIfcType, bool> > expression) where TIfcType : IPersistIfcEntity
{
foreach (var item in cache.Where(expression))
{
yield return(item);
}
}
